Chapter 2 - Major Airframe Components

Question 1

What are the 3 types of joining methods?

Answer 1

Permanent (riveting, adhesives)

Non-permanent (bolting)

Transitional (Pinning, speed tape)

Question 2

What are blind rivets?

Answer 2

Rivets used when access can only be gained to one side of the structure

Question 3

What is a lock wire?

Answer 3

A permanent fixing part of a set of bolts.

The only way to get one off is to destroy it.

Question 4

What are some different construction techniques?

Answer 4

Truss

Monocoque

Semi-monocoque

Question 5

What are the features of a truss structure?

Answer 5

Carries tension and compression loads

Wire braced

longerons provide stiffness

Question 6

What are the features of a monocoque structure?

Answer 6

series of aluminium frames joined by longerons

Metal skin attached around the whole assembly

no internal framework

Skin is partly structural so damage will weaken structure

Question 7

What are the features of a semi-monocoque design?

Answer 7

Skin is only for aerodynamic shape

formers/frames define shape

stringers run longitudinally and help withstand buckling

longerons are the main structural load carrying members

bulkheads provide structural partitions inside fuselage

firewalls are fire resistant bulkheads

Question 8

What is a machined or integral structure and what are the benefits?

Answer 8

Where a single piece of aluminium is machined so that it forms and skin and stringer like structure

there are no need for rivets and therefore it saves weight and is good for wet wings (fuel tanks)

Question 9

Why is a fuselage usually circular?

Answer 9

This prevents airflow separation and it is easier to absorb loads from pressurisation

Question 10

What are the benefits and drawbacks to an oval fuselage cross section?

Answer 10

Benefits:

lower manufacturing costs; greater capacity so increased revenue; better options for cargo loading and unloading.

Drawbacks:

Less ability to withstand hoop loads

Question 11

What is the maximum that a cabin is usually pressured to?

Answer 11

8 or 9 psi

Question 12

What are the purpose of blow out bungs?

Answer 12

if the pressure differential between the cabin and the cargo bay is too high then the bungs will blow out allowing for equalisation.

Question 13

Where do the TE flight controls attach?

Answer 13

The rear spar

Question 14

Where do the LE flight controls attach?

Answer 14

The front main spar.

Question 15

What are the 3 types of wing design?

Answer 15

Cantilever

semi-cantilever

externally braced

Question 16

What is the difference between a cantilever wing and a semi-cantilever wing?

Answer 16

the semi-cantilever wing has struts the extend from the fuselage to a point along the wing.

Question 17

Why don’t high speed jet transport A/C have semi-cantilever wings?

Answer 17

Struts create too much drag

Question 18

What is the normal shape of the main wing spar?

Answer 18

An I beam

Question 19

What is a torsion box?

Answer 19

A section created with spars linking together to form a very rigid, resistant to twisting section, which adds to wing strength.

Question 20

What are the purpose of wing ribs?

Answer 20

to provide aerodynamic shape; allow stressed skin to be attached; transfer loads to the spars.

Question 21

What is a wet wing?

Answer 21

Wing spaces that allow for storage of fuel.